The subject invention relates to roofing membranes and in particular to a roofing membrane temperature indicator that enables a roofing contractor to readily determine whether the temperature of a roofing membrane or a plurality of roofing membranes in a package is suitable for the installation of the roofing membrane(s) in a roofing system and thereby prevent an inadvertent installation of the roofing membrane(s) in a roofing system at a temperature below a minimum recommended installation temperature for the roofing membrane(s) and/or a minimum recommended installation temperature for the membrane(s) for a particular roofing membrane installation procedure.
Asphaltic roofing membranes with smooth or granular top surfaces, other roofing membranes (such as but not limited single ply PVC, TPO, and EPDM membranes sold by Johns Manville International, Inc. and other roofing product manufactures), and asphaltic, single ply, or other roofing membranes that have smooth or granular thermochromic top surfaces that undergo a visible color change at a specific temperature to promote energy conservation within a building should only be installed under conditions that conform to the application specifications set forth by the manufacturer. These application specifications permit the application of these roofing membranes only when the roofing membranes are at temperatures that are at or above minimum recommended installation temperatures. By requiring these roofing membranes to be at or above minimum recommended installation temperatures, the roofing membranes are not damaged during application due to a lack of sufficient pliability and good strong bonds are formed between the individual roofing membranes of a roofing layer and the roofing membranes of that layer and an underlying roofing layer. In general, application specifications require the roofing membranes set forth in this paragraph to be installed in a roofing system only when the roofing membranes are at temperatures of 40° F. (4° C.) or higher. Where these roofing membranes are self-adhering roofing membranes, the adhesion of these roofing membranes to other roofing membranes and roofing layers is highly dependent on the temperatures of the roofing membranes at the time of installation. Thus, these self-adhering roofing membranes should only be installed when the temperatures of these roofing membranes are sufficiently high to assure a good strong bond between these roofing membranes and between these roofing membranes and other roofing layers e.g. at temperatures of 50° F. (10° C.) or higher.
When a roofing system is being installed, the ambient temperature and the temperature of the roofing membranes to be installed in the roofing system may not and frequently do not coincide. Thus, ambient temperature alone cannot be relied upon to determine whether conditions are acceptable for the installation of the roofing membranes. For example, while the ambient temperature at the job site might be 40° F. or higher, the temperature of the roofing membranes to be installed, e.g. after being stored at the job site over night, might not be at or above the temperature required to meet application specifications, but at a temperature below that required to meet application specifications, e.g. at a temperature below 40° F. By way of another example, self-adhering roofing membranes should be at or above a specified temperature to meet application specifications, e.g. at or above 50° F. (10° C.), but can be installed when ambient temperatures are less than that temperature, e.g. at temperatures of 45° F. (7° C.) and rising during installation. Thus, a contractor cannot rely solely on knowing the ambient temperature when determining if application specifications for a roofing membrane are being met during the installation of the roofing membrane. The contractor must know both the ambient temperature and whether or not the roofing membranes to be installed are at or above a minimum recommended installation temperature for the roofing membranes.